Deflection prism assembly for an endoscope having a lateral viewing direction, endoscope having a lateral viewing direction and method for assembling a deflection prism assembly

ABSTRACT

A deflection prism assembly for an endoscope having a lateral viewing direction. The deflection prism assembly including: a prism holder; and a deflection prism which is received in the prism holder. The deflection prism is formed of a glass. The prism holder includes a reception component and an adjustment component, where the reception component is formed of a ceramic and the adjustment component is formed of a metal. The deflection prism is attached to the reception component and the adjustment component provides a stop for the deflection prism in an axial direction.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of PCT/EP2019/065137 filed onJun. 11, 2019, which is based upon and claims the benefit to DE 10 2018115 238.8 filed on Jun. 25, 2018, the entire contents of each of whichare incorporated herein by reference.

BACKGROUND Field

The present disclosure relates to a deflection prism assembly for anendoscope having a lateral viewing direction, comprising a prism holderand a deflection prism, which is received in the prism holder, whereinthe deflection prism is produced from a glass. Moreover, the presentdisclosure relates to an endoscope having a lateral viewing directionand a method for assembling a deflection prism assembly.

Prior Art

In the medical field, both endoscopes which look forwards frontally andendoscopes having a viewing direction which deviates by an angle greaterthan 0° from said frontal viewing direction are deployed. In the lattercase, these are referred to as endoscopes having a lateral viewingdirection.

Distal deflection prisms are frequently deployed in endoscopes having alateral viewing direction. The distal deflection prisms are mostlycomposed of multiple sub-prisms and serve to deflect diagonally incidentlight such that it runs parallel to a longitudinal axis of the endoscopeshaft.

Deflection prisms have to satisfy a plurality of requirements. Adeflection prism should be embodied such that light from as large aspossible a field of view can enter the endoscope and be forwarded intothe optical system of the endoscope. Simultaneously, the dimensions ofthe deflection prism must be small enough that it can be arranged andattached in the endoscope shaft. In addition, the deflection prism mustbe aligned in the endoscope such that incident light bundles areforwarded in the manner provided. If the deflection prism is notcorrectly aligned, image errors or a deterioration of the image qualitycan occur.

Conventionally, a lateral face of the deflection prism is completelysurrounded by a cylinder-shaped prism holder. This prism holder receivesthe deflection prism, attaches it and serves as a reference system foraligning the deflection prism in the endoscope. It is disadvantageousthat a cylinder-shaped prism holder of this type limits the maximumdimensions of the deflection prism in the radial direction.

Document DE 10 2017 124 593 of the applicant Olympus Winter & Ibe GmbH,Hamburg, which has not previously been published, discloses a deflectionprism assembly which comprises a deflection prism and a prism holder.The lateral face of the deflection prism is only surrounded by the prismholder in certain regions so that the deflection prism can be embodiedlarger in the radial direction in the region which is not enclosed bythe prism holder. In this way, more light travels through the deflectionprism into the optical system of the endoscope.

In order to be able to exactly receive the deflection prism with respectto the optical axis of the endoscope, the prism holder must bemanufactured exactly. The prism holder must therefore be produced from amaterial that allows an exact production and processing with respect toits dimensions. Metals, e.g. brass or austenitic steel, are suitable forthis purpose.

It is true that these materials make it possible to manufacture theprism holder exactly, however it is disadvantageous that the thermalexpansion coefficient of such a metal differs significantly from thethermal expansion coefficient of the glass, from which the deflectionprism is manufactured. This can lead to technical difficulties duringthe attachment of the deflection prism in the prism holder. Thehigh-strength and temperature-stable adhesive deployed to attach thedeflection prism must be vigorously heated during curing. Due to thedifferent thermal expansion coefficients, tensions occur between thedeflection prism and the prism holder during this process, which canlead to a fracture of the deflection prism.

FIG. 2 shows a schematically simplified representation of a longitudinalsection through a deflection prism assembly 13, as it is frequently usedin the prior art.

The deflection prism 16 comprises three sub-prisms 16 a, 16 b, 16 cwhich deflect incident light bundles in the direction of thelongitudinal axis of an endoscope shaft 4. This is shown using theexample of the beam path 19. Incident light bundles along said beam path19 enter through the inlet lens 17, which in this embodiment is likewiseconfigured as the inlet window 10, into the endoscope 2. The lightbundles are subsequently reflected twice in the deflection prism 16 andforwarded through an outlet lens 18 into an optical system (not shown)of the endoscope 2.

The deflection prism 16 comprises a light inlet face 62, a light outletface 64 and a lateral face 66 which extends between the light inlet face62 and the light outlet face 64. The lateral face is cylindrical. In theembodiment shown in FIG. 2, the lateral face 66 of the deflection prism16 is completely enveloped by a substantially cylinder-shaped prismholder 14. As a result of this complete enveloping, the deflection prism16 can indeed be aligned and attached with little outlay in the prismholder 14, but the dimensions of the deflection prism 16 are limited bythe prism holder 14.

FIG. 3 shows a further embodiment of a deflection prism assembly 23 asis shown, for example, in document DE 10 2017 124 593. In thisembodiment of the deflection prism assembly 23, the prism holder 24 onlyencloses the deflection prism 26 in certain regions or in sections. As aresult, the deflection prism 26 can be configured larger in the radialdirection in the distal upper region. The field of view of an endoscope2 having such a deflection prism assembly 23 is therefore larger thanthe field of view of an endoscope 2 having a deflection prism assembly13, as shown by way of example in FIG. 2.

Since the deflection prism 26 in the embodiment shown in FIG. 3 is not,however, enveloped in a circumferential manner by the prism holder 24,the deflection prism 26 has to be attached in the deflection prismassembly 23 with a high-strength and temperature-stable adhesive. Inorder to cure an adhesive of this type, high temperatures are necessary.At these high temperatures, mechanical stresses can occur between thedeflection prism 26 produced from a glass and the prism holder 24produced from a metal, for example a steel alloy.

SUMMARY

An object is to provide a deflection prism assembly, an endoscope havinga lateral viewing direction and a method for assembling a deflectionprism assembly, with which both a high optical quality and reliable andefficient manufacture of the deflection prism assembly and of theendoscope can be achieved.

Such object can be solved by a deflection prism assembly for anendoscope having a lateral viewing direction, comprising a prism holderand a deflection prism, which is received in the prism holder, whereinthe deflection prism is produced from a glass, the prism holdercomprises a reception component and an adjustment component, wherein thereception component is produced from a ceramic and the adjustmentcomponent is produced from a metal, wherein the deflection prism isattached to the reception component and the adjustment componentprovides a stop for the deflection prism in an axial direction.

The prism holder comprises two components: a reception component and anadjustment component. The reception component is configured to receivethe deflection prism and is produced from a ceramic. Said ceramic can beselected such that the thermal expansion coefficient of the ceramicsubstantially coincides with the thermal expansion coefficient of theglass, from which the deflection prism is produced. Even if it is notnecessary or possible for the thermal expansion coefficients tocorrespond exactly, the ceramic can be, however, selected such that itsthermal expansion coefficient differs from the thermal expansioncoefficient of the glass by less than a predefined threshold value. Thiscan prevent the deflection prism tensing mechanically with respect tothe reception component when the deflection prism assembly is heated.The probability of damage to the deflection prism group can thus besubstantially reduced during this process.

The adjustment component serves to axially align the deflection prism.It provides a stop for the deflection prism, on which stop thedeflection prism is brought to rest, indirectly or directly. If thedeflection prism is brought to rest directly, it is in direct contactwith the stop. The material of the adjustment component is a metal. Acomponent made of a metal can be produced more precisely than acomponent made of ceramic. The adjustment component can be reworked bycutting. Thus, a high precision can be achieved during the alignment ofthe deflection prism.

A mask can be arranged between the deflection prism and the stop, whichmask can act as a spacer. In such a case, the deflection prism can bebrought to rest indirectly on the stop.

Within the context of the present description, the term “axialdirection” is understood to be a direction which runs parallel to alongitudinal axial direction of the endoscope shaft, to which thedeflection prism assembly is attached. An “axial alignment” isaccordingly an alignment of a component in said axial direction.

The adjustment component, which is a part of the prism holder, can allowthe deflection prism to be precisely aligned in the deflection prismassembly. As a result, a high optical quality of the deflection prismassembly and of an endoscope having such a deflection prism assembly isattained.

According to an embodiment, the adjustment component can be producedfrom a non-ferromagnetic metal, such as a non-ferromagnetic steel alloy.For example, the adjustment component can be produced from the steelalloy having the material number 1.4305. Magnetic actuators, with whichthe axial position of optical elements can be modified, for example, canbe arranged in optical systems of endoscopes. The production of theadjustment component from a non-ferromagnetic metal can prevent themagnetic actuators being adversely affected by the adjustment component.

At least one electrical heating element for heating the deflection prismassembly can be present in or on the reception component or integratedinto the reception component, wherein the electrical heating element canrun at least in sections within the reception component.

The electrical heating element can be arranged on a surface of thereception component. The heating element can be arranged on an outerside which faces away from the deflection prism assembly. Two differentembodiments can be provided: a first embodiment in which the electricalheating element can be integrated into the reception component, and asecond embodiment in which the electrical heating element can bearranged on a surface of the reception component.

The integration of a heating element into the reception component or thearranging of the electrical heating element on the reception componentcan provide warming of the deflection prism assembly, if necessary.During the practical deployment of the endoscope, optical faces can mistup, for example the inlet window or the optical faces of the deflectionprism assembly, as a result of which the image quality is considerablyrestricted. By warming the deflection prism assembly, the optical facescan be freed from the condensation so that there is a clear view again.

Producing the reception component from a ceramic to act as an electricalinsulator is exploited during the arrangement of the electrical heatingelement. Electrical insulation between the electrical heating elementand the reception component can be dispensed with.

The heating element can be a structure made of a conductive material,which structure can be printed onto the reception component or, thanksto the multilayer construction of the ceramic, can be integrated intothe structural body produced from the ceramic. In order to establish anelectrical contact with this heating element, a thin printed circuitboard can be used.

When such a reception component made of ceramic and a heating element ofthis type are used, the deflection prism can be embodied to be largerthan is the case with a prism holder which is completely produced from aconductive metal. Installation space can of course be saved bydispensing with the electrical insulation.

At least one temperature sensor can be present in or on the receptioncomponent.

Such a temperature sensor can be a thermistor which is configured as anegative temperature coefficient thermistor or as a positive temperaturecoefficient thermistor. The temperature at the location of thedeflection prism assembly can be monitored by the temperature sensor.The temperature sensor can be deployed in conjunction with an electricalheating element, in order to monitor the warming attained by theelectrical heating element. As is also the case with the electricalheating element, the temperature sensor, due to the production of thereception component from a ceramic, without using additional insulation,can be printed onto the surface of the reception component or integratedinto the reception component.

The adjustment component can provide reference points for the radialalignment of the deflection prism.

Within the context of the present specification, the term “radialdirection” is understood to be a direction which runs vertically to thelongitudinal axial direction of the endoscope shaft, to which thedeflection prism assembly is attached. A “radial alignment” is analignment in this radial direction.

Due to the reference points of the adjustment component, the radialalignment of the deflection prism can also be performed exactly due tothe precise production of the adjustment component. The reference pointscan be configured to interact with an adjustment device which lies incontact with at least three, such as four, regions of the lateral faceof the deflection prism. These regions can be points. For example, it isprovided that such an adjustment device, viewed in a plane vertical tothe longitudinal axial direction, can act upon points at 9 o'clock,twelve o'clock and three o'clock. If an adjustment device which actsupon four points is provided, these are for example the points spacedapart by 90° at twelve o'clock, three o'clock, six o'clock and nineo'clock.

Due to the use of an adjustment device of this type, the adjustmentcomponent, which can be precisely manufactured and aligned, can be usedas a reference system for the radial alignment of the deflection prism.

According to a further embodiment, the deflection prism can have a lightoutlet face and an opposite light inlet face arranged diagonallythereto, between which a lateral face extends, wherein the prism holderreceives the deflection prism in such a way that the prism holder simplysurrounds the lateral face of the deflection prism in sections, such asdoes not surround it completely. The prism holder can be, in otherwords, embodied such that it simply rests on the lateral face of thedeflection prism in sections, that is to say it does not surround a partof the lateral face.

The prism holder can lie in contact with the lateral face of the prismin a first region, wherein a second region of the deflection prismradially opposite the first region is not surrounded by the prismholder.

Such an embodiment of the prism holder offers, for example, a simplifiedassembly while simultaneously improving the optical imaging quality. Theeffective cross-sectional area of the prism for the light entry can,moreover, be increased without the installation space of the entire unitincreasing. The provision of an adjustment component and a receptioncomponent simultaneously prevents tensioning of the deflection prismoccurring during curing of an adhesive between the deflection prism andthe prism holder. Consequently, a high optical quality is achieved atthe same time as reliably and efficiently assembling the deflectionprism assembly.

The light outlet face of the deflection prism can lie in contact withthe stop of the adjustment component. The deflection prism can lie incontact with the stop of the adjustment component with a stop face whichis oriented parallel to the light outlet face. The reception componentcan surround exclusively the lateral face of the deflection prism incertain regions or in sections, as previously described; by contrast,the adjustment component does not have to surround the lateral face ofthe deflection prism in any region since it does not have to come intocontact with the lateral face of the deflection prism. In this way, itis ensured that a tensioning does not occur between the deflection prismand the adjustment component when the deflection prism assembly isheated.

The deflection prism can be exclusively attached to the receptioncomponent, such as by means of an adhesive. This measure can ensure thatthe deflection prism is securely attached in the deflection prismassembly and, simultaneously, the attachment does not adversely affectthe alignment of the deflection prism. Such an adverse effect wouldoccur, for example, if an adhesive layer were to form between thedeflection prism and the stop.

At least one adhesive gap can be present between the deflection prismand the reception component, wherein the at least one adhesive gap has agap width which is large enough that, taking account of manufacturingtolerances, the deflection prism does not lie in contact with thereception component at any point.

The adhesive gap can be filled with an adhesive. Providing an adhesivegap ensures that the deflection prism is, on the one hand, securelyattached in the deflection prism assembly and, on the other hand, thedeflection prism does not lie in contact with the reception component atany point. In this way it is ensured that, despite the fluctuationswhich can occur with the dimensions of the reception component by virtueof the fact that the reception component is produced from a ceramic, thedeflection prism does not touch the reception component at any point.Thus, the deflection prism can be exclusively aligned radially andaxially by the stop and the reference points of the adjustmentcomponent.

The reception component can be attached to the adjustment component,such as by means of an adhesive.

The reception component can be attached and, can also be aligned bymeans of the adjustment component. Due to the precise production of theadjustment component, this constitutes a suitable reference system notonly for the deflection prism but also for the reception component. Theadjustment component can comprise a guide which is configured as anaxial and/or radial slide bearing. The adjustment component can beconnected to the optical system of an endoscope by means of said guide.The slide bearings can allow a rotation of the deflection prism assemblyin order to modify the viewing direction of the endoscope as well as anadjustment of the distance between the deflection prism and the opticalsystem.

Such object can also be solved by an endoscope having a lateral viewingdirection, comprising a deflection prism assembly according to any oneof the previously indicated embodiments.

Such object can also be solved by a method for assembling a deflectionprism assembly according to any one of the previously indicatedembodiments, wherein the method comprises: attaching the adjustmentcomponent to an optical system of an endoscope, fitting the receptioncomponent onto the adjustment component and attaching the receptioncomponent to the adjustment component, inserting the deflection prisminto the prism holder, axially aligning the deflection prism by bringingthe deflection prism to rest on the stop of the adjustment component,and attaching the deflection prism to the reception component.

The endoscope can have a lateral viewing direction and the method forassembling a deflection prism assembly have the same or similaradvantages to those which have already been mentioned above with respectto the deflection prism assembly, so repetitions shall be dispensedwith.

The axially aligning of the deflection prism can comprise indirectly ordirectly bringing the deflection prism to rest on the stop of theadjustment component. According to an embodiment, a mask can be arrangedon the light outlet face, so that the deflection prism can be indirectlybrought to rest on the stop of the adjustment component.

The reception component can be aligned when it is fitted on theadjustment component. In addition, the features of the method can beexecuted one after the other in the order in which they are enumerated.Consequently, the adjustment component can be first attached to theoptical system and precisely aligned with respect to the latter. Thereception component can be subsequently positioned on the adjustmentcomponent and attached to the latter, such as by means of an adhesive.Since the adjustment component can be configured to align the deflectionprism, the alignment of the reception component requires a lowerprecision than is the case during the alignment of the adjustmentcomponent and the deflection prism. Following the attaching of thereception component, the deflection prism can be inserted into the prismholder and can be aligned in the reference system of the adjustmentcomponent before the deflection prism is definitively attached to thereception component. The adhesive used to attach the deflection prismcan be applied to the reception component prior to inserting thedeflection prism and can be cured following the aligning of thedeflection prism.

The deflection prism can be radially aligned by means of an adjustmentdevice, wherein the adjustment device can be positioned on thedeflection prism assembly, interact with reference points of theadjustment component and lie in contact with at least three regions orpoints of the lateral face of the deflection prism.

Thanks to the use of an adjustment device of this type, themanufacturing accuracy during the production of the adjustment devicecan also be utilized for the radial alignment of the deflection prism.An adjustment device of this type can have, for example, a substantiallycylindrical form which interacts at one end with the reference points ofthe adjustment component and, at its other end, can lie in contact withat least three regions of the lateral face of the deflection prism. Thereception component can have one or more recesses, through which theadjustment device for aligning the deflection prism engages, in order tolie in contact with the lateral face of the deflection prism.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features will become evident from the description ofembodiments, together with the claims and the appended drawings.Embodiments can fulfill individual features or a combination of multiplefeatures.

The embodiments are described below without limiting the general conceptof the invention by means of exemplary embodiments with reference to thedrawings, wherein reference is expressly made to the drawings regardingall of the details which are not explained in greater detail in thetext, wherein:

FIG. 1 illustrates a schematically simplified perspective representationof an endoscope,

FIG. 2 illustrates a schematically simplified longitudinal sectionthrough a deflection prism assembly having an inlet lens, an outlet lensand a prism holder completely enclosing the deflection prism,

FIG. 3 illustrates a schematically simplified longitudinal sectionthrough a deflection prism assembly having an inlet lens, an outlet lensand a prism holder only enclosing the deflection prism in certainregions, which is configured in one piece,

FIG. 4 illustrates a schematically simplified cross-sectional viewthrough a deflection prism assembly having an inlet lens, an outlet lensand a prism holder which comprises a reception component and anadjustment component,

FIG. 5 illustrates a schematically simplified perspective representationof the deflection prism assembly from FIG. 4, and

FIG. 6 illustrates a schematically simplified cross-sectional viewthrough a deflection prism assembly having an inlet lens, an outlet lensand a prism holder which comprises a reception component, an adjustmentcomponent and a mask.

In the drawings, the same or similar elements and/or parts are, in eachcase, provided with the same reference numerals so that they are notintroduced again in each case.

DETAILED DESCRIPTION

FIG. 1 shows an endoscope 2 having a lateral viewing direction. At aproximal end of the endoscope 2 there is located a handle 4, to which ashaft 6 or an endoscope shaft is joined. At a distal end 8 of the shaft6 there is located an inlet window 10, through which light bundles froman observation or operating field located distally in front of thedistal end 8 enter the interior of the shaft 6. In a distal end region12 of the shaft 6, a deflection prism 16 is arranged as part of adeflection prism assembly 13 within the shaft 6.

FIG. 4 shows an embodiment of a deflection prism assembly 33 whichcombines the optical properties of the deflection prism assembly 23 fromFIG. 3 with the reliable production of the deflection prism assembly 13from FIG. 2. The deflection prism assembly 33 comprises the deflectionprism 36 and a prism holder 34 which, in turn, comprises a receptioncomponent 42 and an adjustment component 46. The inlet lens 37 shown inFIG. 4, the outlet lens 38, the outer casing 52 or the optical system 50are, by contrast, not part of the deflection prism assembly 33.

The inlet lens 37 and the outlet lens 38 correspond to the inlet lens 17and the outlet lens 18 from FIGS. 2 and 3. The deflection prism 36having the sub-prisms 36 a, 36 b, 36 c corresponds to the deflectionprism 26 having the sub-prisms 26 a, 26 b, 26 c from FIG. 3. Unlike theprism holder 14 and the prism holder 24, the prism holder 34 in FIG. 4is, however, composed of two separate components, the receptioncomponent 42 (hatching from top right to bottom left) and the adjustmentcomponent 46 (hatching from top left to bottom right).

The adjustment component 46 is substantially cylinder-shaped andcomprises in its distal region the outlet lens 38. The proximal regionof the adjustment component 46 is executed as an axial and radial slidebearing for the optical system 50 of the endoscope 2. This allows arotation of the deflection prism assembly 33 in order to modify theviewing direction of the endoscope 2 as well as an adjustment of thedistance between the deflection prism 36 or respectively the lightoutlet lens 38 and the optical system 50.

Furthermore, the adjustment component 46 provides a stop 48 for thelight outlet face 64 of the deflection prism 36, with which thedeflection prism 36 is aligned in the axial direction. To ensure thatthe alignment of the deflection prism 36 is as exact as possible, thedimensions of the adjustment component 46 have to be precisely observed.For this reason, a metal, for example brass or a steel alloy, is used toproduce the adjustment component 46. If the optical system 50 comprisesmagnetic actuators, the adjustment component 46 is produced from anon-ferromagnetic metal so as not to adversely affect the magneticactuators.

The reception component 42 is positioned on the adjustment component 46and, for example, attached to the latter by means of an adhesive. Saidreception component 42 substantially corresponds to the region of theprism holder 24 from FIG. 3, which comprises the lateral face 66 of thedeflection prism 26. In other words, the deflection prism 36 isexclusively received in the reception component 42 of the prism holder34 and is also exclusively attached to said reception component 42. Anadhesive, which is applied in the adhesive gaps 68 between thedeflection prism 36 and the reception component 42, is used for theattaching. Said adhesive gaps 68 are configured so large that, takingaccount of production-related deviations in the dimensions of thereception component 42, the deflection prism 36 does not lie in contactdirectly with the reception component 42 at any point.

In contrast to the adjustment component 46, the reception component 42is produced from a ceramic. Said ceramic has a thermal expansioncoefficient which substantially corresponds to the thermal expansioncoefficient of the glass used to produce the deflection prism 36. Thisprevents a tensioning between the deflection prism 36 and the receptioncomponent 42 during curing of the adhesive in the adhesive gaps 68.Inaccuracies in the dimensions of the reception component 42, which arecaused by the use of the ceramic to produce said component, do not haveany influence on the alignment of the deflection prism 36 since thelatter, as previously explained, does not lie in contact with thereception component 42 at any point.

The shaft 6 of the endoscope 2 is surrounded by an outer casing 52 up tothe distal end region 12. Said outer casing 52 has, in the region of theadjustment component 46, multiple circular recesses 54, for example fourrecesses 54 which, observed in a plane vertical to the longitudinalaxial direction, are arranged at points at twelve o'clock, threeo'clock, six o'clock and nine o'clock. In FIG. 4, for illustrationreasons, only the recesses 54 at twelve o'clock and six o'clock areshown. Below these recesses 54, the adjustment component 46 providesreference points 49 which interact with an adjustment device which isnot shown. Said adjustment device comprises, in addition, the deflectionprism 36 on at least three sides, for example at nine o'clock, twelveo'clock and three o'clock so that the deflection prism 36 can beradially aligned in the reference system of the adjustment component 46by means of the adjustment device. In addition, in the embodiment shownin FIG. 4, the reception component 42 has a recess 44, through which theadjustment device can also be brought to rest from below, that is to sayat six o'clock, on the deflection prism 36.

An electrical heating element 70 is integrated in the receptioncomponent 42. Since the reception component 42 is manufactured from aceramic, the provision of an electrical insulating layer between theheating element 70 and the reception component 42 is superfluous. Inorder to mount the electrical heating element 70, printed circuit boardsof an electrically conductive material are mounted on the electricallyinsulating ceramic. If this happens during the production of theceramic, the heating element 70 is integrated in this way betweenmultiple layers of the ceramic. The electrical contacting of the heatingelement 70 happens, for example, through a thin circuit board which isnot shown in FIG. 4.

Thanks to the heating element 70, the deflection prism assembly 33 canbe warmed up, for example in order to evaporate liquid droplets orrespectively condensation which has/have been deposited on the inletlens 37 or the optical faces of the deflection prism assembly 33.

Furthermore, a temperature sensor 80 is integrated or mounted in thereception component 42. Such a temperature sensor 80 is, for example, athermistor configured as a negative temperature coefficient thermistoror positive temperature coefficient thermistor. The temperature sensor80 is mounted or integrated in the same way as the heating element 70.

In the region of the recess 44, the heating element 70 and thetemperature sensor 80 are represented with a dashed line, in order toindicate that the heating element 70 and the temperature sensor 80, inthe region of the recess 44, run around said recess 44.

FIG. 5 shows a simplified representation in perspective of thedeflection prism assembly 33 from FIG. 4. In this representation, it canbe clearly seen that the prism holder 34 only envelopes the deflectionprism 36 in certain regions. In addition, the position and the form ofthe recess 44 and of the recesses 54 are clear. However, the position,number and form of the recesses 44, 54 can differ from therepresentation in FIG. 5.

The part of the prism holder 34 which is visible in FIG. 5 is thereception component 42 produced from a ceramic, while only the referencepoints 49 of the internal adjustment component 46 are visible.

FIG. 6 shows a further embodiment of the deflection prism assembly 33.In contrast to the embodiment according to FIG. 4, a mask 90 is arrangedas a spacer between the stop 48 and the light outlet face 64 of thedeflection prism 36 in the embodiment according to FIG. 6. Thedeflection prism 36 is therefore brought to rest indirectly on the stop48. Moreover, the heating element 70 is not integrated into thereception component 42 in the embodiment according to FIG. 6, but isarranged on the surface of the reception component 42. Said surface ofthe reception component 42 is, for example, as shown in FIG. 6, theoutwardly directed face of the upper portion of the reception component42. In addition, the temperature sensor 80 is integrated into the upperportion of the reception component 42 in the embodiment shown in FIG. 6.

While there has been shown and described what is considered to bepreferred embodiments, it will, of course, be understood that variousmodifications and changes in form or detail could readily be madewithout departing from the spirit of the invention. It is thereforeintended that the invention be not limited to the exact forms describedand illustrated, but should be constructed to cover all modificationsthat may fall within the scope of the appended claims.

LIST OF REFERENCE NUMERALS

-   -   2 Endoscope    -   4 Handle    -   6 Shaft    -   8 Distal end    -   10 Inlet window    -   12 Distal end region    -   13 Deflection prism assembly    -   14 Prism holder    -   16 Deflection prism    -   16 a-16 c Sub-prism    -   17 Inlet lens    -   18 Outlet lens    -   19 Beam path    -   23 Deflection prism assembly    -   24 Prism holder    -   26 Deflection prism    -   26 a-26 c Sub-prism    -   33 Deflection prism assembly    -   34 Prism holder    -   36 Deflection prism    -   36 a-36 c Sub-prism    -   37 Inlet lens    -   38 Outlet lens    -   42 Reception component    -   44 Recess    -   46 Adjustment component    -   48 Stop    -   49 Reference point    -   50 Optical system    -   52 Outer casing    -   54 Recess    -   62 Light inlet face    -   64 Light outlet face    -   66 Lateral face    -   68 Adhesive gap    -   70 Heating element    -   80 Temperature sensor    -   90 Mask

What is claimed is:
 1. A deflection prism assembly for an endoscopehaving a lateral viewing direction, the deflection prism assemblycomprising: a prism holder; and a deflection prism which is received inthe prism holder; wherein the deflection prism is formed of a glass; theprism holder comprises a reception component and an adjustmentcomponent, the reception component being formed of a ceramic and theadjustment component being formed of a metal; and the deflection prismis attached to the reception component and the adjustment componentprovides a stop for the deflection prism in an axial direction.
 2. Thedeflection prism assembly according to claim 1, further comprising atleast one electrical heating element for heating the deflection prismassembly, the at least one heating element being disposed in or on thereception component.
 3. The deflection prism assembly according to claim2, wherein the electrical heating element runs at least in sectionswithin the reception component.
 4. The deflection prism assemblyaccording to claim 2, further comprising at least one temperature sensordisposed in or on the reception component.
 5. The deflection prismassembly according to claim 1, wherein the adjustment component isconfigured to provide reference points for radial alignment of thedeflection prism.
 6. The deflection prism assembly according to claim 1,wherein the deflection prism comprises a light outlet face and anopposite light inlet face arranged diagonally relative to the lightoutlet face, a lateral face extending between the light outlet face andthe light inlet face, wherein the prism holder receives the deflectionprism such that the prism holder only surrounds the lateral face of thedeflection prism in certain regions.
 7. The deflection prism assemblyaccording to claim 1, wherein the deflection prism is exclusivelyattached to the reception component.
 8. The deflection prism assemblyaccording to claim 7, wherein the deflection prism is attached to thereception prism with an adhesive.
 9. The deflection prism assemblyaccording to claim 8, wherein at least one adhesive gap is disposedbetween the deflection prism and the reception component, the at leastone adhesive gap having a gap width such that no portion of thedeflection prism contacts with the reception component.
 10. Thedeflection prism assembly according to claim 1, wherein the receptioncomponent is attached to the adjustment component.
 11. The deflectionprism assembly according to claim 10, wherein the reception component isattached to the adjustment component with an adhesive.
 12. An endoscopehaving a lateral viewing direction, the endoscope comprising: a shaftconfigured to be inserted into a subject; and the deflection prismassembly according to claim 1 disposed on the shaft.
 13. A method forassembling the deflection prism assembly according to claim 1, themethod comprising: attaching the adjustment component to an opticalsystem of the endoscope, fitting the reception component onto theadjustment component and attaching the reception component to theadjustment component, inserting the deflection prism into the prismholder, axially aligning the deflection prism by bringing the deflectionprism to rest on the stop of the adjustment component, and attaching thedeflection prism to the reception component.
 14. The method according toclaim 13, further comprising radially aligning the deflection prism withan adjustment device by positioning the adjustment device on thedeflection prism assembly to interact with reference points of theadjustment component and to lie in contact with at least three regionsof the lateral face of the deflection prism.